1. Field of the Invention
The present invention relates to hinges and more particularly, to a hinge structure with position-locking engagement means, which comprises a pivot shaft inserted through a bracket and a support, and engagement means provided between the bracket and the support for locking the bracket to the pivot shaft when the bracket is turned about the pivot shaft through a predetermined angle.
2. Description of the Related Art
A consumer electronic product with a lifting cover such as mobile computer, electronic dictionary, mobile video player, cell phone, etc., commonly uses a hinge to coupled the cover to the base member so that the cover can be opened from or closed on the base member. Therefore, the hinge determines the quality level of the product. A good hinge allows positive positioning, and does not cause noises during operation.
In recent years, advanced 3C electronic products have been continuously created. The conventional single hinge design to have the cover be turnable relative to the base member in a particular direction cannot satisfy the demand. Therefore, two pivot type hinge structures are developed for enabling the cover to be rotated relative to the base member when opened from the base member. Taiwan patent M304879 discloses a multiplex hinge issued to the present inventor, entitled “HINGE STRUCTURE”. According to this design, the hinge structure comprises a bracket, which has a horizontal base panel and a vertical side panel, a first pivot set inserted through the side panel of the bracket and rotatably coupled to a support and having two elongated ribs protruded from one end of the pivot shaft and a guide groove defined between the elongated ribs, and a second pivot set inserted through the horizontal base panel of the bracket and rotatably coupled to a mounting frame and having a two flat cut faces at two sides of the head of the pivot shaft thereof for stopping against the elongated rids of the pivot shaft of the first pivot set such that the second pivot set is locked when the first pivot set is not turned to the predetermined angle, or unlocked for rotation when the first pivot set is turned to the predetermined angle. The first pivot set further comprises a supplementary plate member mounted on the pivot shaft of the first pivot set and having two raised portions corresponding to respective slots on the side panel of the bracket, and a limiter mounted on the pivot shaft of the first pivot set between the side panel of the bracket and the support. The raised portions of the supplementary plate member are respectively engaged into the slots of the side panel of the bracket when the first pivot set is rotated to the predetermined angle. The limiter has two protrusions spaced from each other at an angle and alternatively stoppable against a stop rod at the side panel of the bracket to limit the angle of rotation of the first pivot set relative to the bracket.
According to the aforesaid design, the through hole on the side panel of the bracket through which the pivot shaft of the first pivot set is inserted is spaced behind the center of the side panel at a distance about 1.2 mm, the raised portions of the supplementary plate member may be not all accurately engaged into the slots of the side panel of the bracket when the first pivot set is rotated to the predetermined angle. Therefore, an improvement is necessary.